Can't move aperture setting on Canon FD lens

[Herbc]

I got a very clean 300mm f4 Canon FD lens to use on my A7RII, and as I already have a couple of FD lenses, I expected this one to be no problem.  For some reason, when I put the lens on the adapter and then onto the camera, the f stop is set at f32 on the lens and will not move.  The small black button on the aperture ring does not seem to work to release the ring, but my other FD's have no problem with this.

Any wisdom for loosening this ring?

 

[Bart_van_der_Wolf]

I got a very clean 300mm f4 Canon FD lens to use on my A7RII, and as I already have a couple of FD lenses, I expected this one to be no problem.  For some reason, when I put the lens on the adapter and then onto the camera, the f stop is set at f32 on the lens and will not move.  The small black button on the aperture ring does not seem to work to release the ring, but my other FD's have no problem with this.

Any wisdom for loosening this ring?

Hi,

Do you have the lens set in automatic, or manual aperture mode?

At the rear end of the lens, there is a longer protruding mechanical connection lever that can be slid counter-clockwise until it locks in place. When you then mount the lens, the manual aperture can be set. If it is slid clockwise there will be a spring action that will be used by the camera/adapter to automatically close and open the aperture.

Cheers,
Bart

[Herbc]

thanks Bart- the lever won't lock in a counter clockwise position.  I think I may have a repair issue.
When mounted on a fotodiox adapter, I can move the aperture inside the lens with the adapter's blue ring, but the aperture setting on the lens cannot be moved.  I think a repair dude may be in order.

[Herbc]

Ok, stupid is as stupid does- turns out I was not using enough force to push the black button in to move the aperture ring, which is pretty stiff, but ok.
Any ideas about how to loosen the ring?